Graphene is a molecule comprising a single layer of carbon atoms bound together, typically by sp2 bonds, in the form of a hexagonal structure. Graphene has a number of desirable thermal and mechanical properties, including high thermal conductivity (5,000 W/mK), high-electron carrying capacity at room temperature (250,000 cm3/Vs), high tensile strength, and high mechanical stability, with Young's modulus of 1 TPa. The properties of graphene make it useful in a large number of applications, such as sensors, batteries, supercapacitors, hydrogen storage systems and as reinforcement fillers of nanocomposites.
Graphene sheets can be in the form of single or multiple layers of graphene however the current methods for making graphene sheets are limited.
Existing methods for preparing graphene sheets include, chemical vapour deposition (CVD) onto a metal (i.e. foil) substrate, chemical exfoliation, mechanical exfoliation of graphite, epitaxial growth, carbon nanotube cutting and direct sonication. These methods all have their own advantages and disadvantages, particularly with regards to cost and scalability. Current methods require extensive filtering, chemical separation processes, chemical etching processes and other environmentally unclean steps to create a functional material. In addition these methods are not well suited for large scale manufacturing.